Don't feel bad. At two weeks into the course it's perfectly fine to feel you're having trouble with some progressions and keeping up with songs, etc. After two months I've found some things come easier than others, and you just have to feel yourself and see what type of practice works best for you.

I'v read that it's not so much the amount of time you put into it, but the quality of that time. I've found that if I do a quick practice of the stuff which comes easy to me (and it will vary for you), I can then focus more time on those darn chord changes that are still hard to come by (to me it's the darned G to C). Regardless of how much progress (or stepping back) you make in each session, don't feel bad at all. Everytime you pick your guitar up and practice with it you're making progress.

I've also found that just learning songs that I like has greatly helped. I take one or two days a week (out of a seven day practice schedule) to just try to learn songs that I like. I try to choose from the suggested songs at each level and just play along. Playing a song that you like should be a bit easier since you can already anticipate chord changes and are familiar with rythm and strumming.

We are all different, and what seems easy for one will be the hardest for another.

Keep at it. I know I've faced a wall or two during the past two months, but I really don't care. I'm in with this for the long run (and I'm 53).

Enjoy!